Examining the soil is crucial when you want to grow healthy plants. A garden or lawn cannot achieve appropriate root development levels without the correct nutrient profile available.
There are some basic test you can do yourself. Soil structure, dig 12 inches down take a clump of soil in your hand. If the soil crumbles nicely then you have good structure. To test PH levels take two tablespoons of soil and add one half cup of vinegar if it fizzles your soil is alkaline. Next do the same only instead of vinegar add baking soda, if it fizzles you have acidic soil. If neither test shows a result your soil is PH neutral.
What Are the Best Ways to Test My Soil?
Regular testing is highly recommended since plant health starts with the soil. Here are the options you can use to get the necessary information.
1. Test the Overall Soil Structure
You can’t tell if the soil is wet or dry by looking at what is visible on the surface. The best way to know if moisture levels are appropriate is to get deeper beyond the initial root structure of most plants and lawns.
Start by digging a small hole about 10 to 12 inches deep. Place the soil from this work in a small tray.
Take the intact soil sample and start breaking it apart with your hands. It should look and feel powdery, cloddy, and granular if it is dry.
If the soil is healthy, it should contain different “crumbs” that hold their shape when light pressure gets applied. When it takes a lot of work to break apart the sample, you know it’s too compact to support root expansion.
Depending on what you discover, you’ll want to add or subtract water. If the soil is too compact, consider aeration or mixing some organic matter into the place where plants will grow.
2. Test Your Soil Composition
Healthy soil is typically about 40% sand, 40% silt, and 20% clay. [[1]]
If this compositional structure gets unbalanced, it can affect drainage, root growth, and other supports to help plants establish themselves successfully.
If you’re unsure of your soil balance, the jar test is an effective way to find out what you’ve got. You’ll need an empty straight-side jar, a lid, and a ruler to ensure your measurements are accurate.
Dig to about six inches before collecting enough soil to fill the jar about halfway full.
You’ll need to fill the jar up to its shoulder with water. Set it aside to let the soil soak up the fluid.
Once the fluid gets absorbed, place the lid on the jar and shake it rapidly and firmly for approximately three minutes.
- After shaking the jar for three minutes, set it down. After 60 seconds, measure the sediment levels that collected at the bottom to see how much sand is in the soil.
- Wait at least four minutes to measure the sediment a second time. Subtract the number you receive from the sand to get the silt levels in the soil.
- The third measurement requires 24 hours to complete. You’ll take the difference between the second and final numbers to determine how much clay is present.
After you have those figures, you can calculate the approximate percentage of the soil materials.
If you have too much sand, it helps to add peat moss, aged manure, or sawdust. When silt is the issue, add coarse sand, compost, or gravel to create improvements.
Add coarse sand, peat moss, and compost when you have too much clay.
3. Test the Soil for Workability
When soil is workable, it allows water to move efficiently from the surface to the plant’s roots. If you can’t move it around with a standard rake, you’ll know it is too compact to be useful for other needs.
The soil might produce clods or plates while using the rake. That outcome is still evidence that low workability exists.
It helps to have enough movement where it doesn’t feel like heavy labor to create planting options. When the soil has no staying power after working through it, you might need to add compost or other nutrients because the materials are too fine.
4. Test the Soil for its pH level.
Some plants want to have acidic soil, while others prefer something more neutral. You might even have an alkaline base that requires adjustment. We look at the best pH for garden soil in this article.
You can get an idea of your soil pH with a simple at-home test.
- Place two tablespoons of soil that you took from at least six inches beneath the surface in a bowl.
- Add 1/2-cup vinegar to the soil. If the mixture fizzes, you have an alkaline result.
- If you don’t get a reaction, take another two tablespoons of soil and place them in a different bowl.
- Moisten it with distilled water, adding 1/2-cup baking soda to the mix. If it fizzes, you have acidic soil.
- When neither action occurs, you know that you have a neutral pH.
Most plants absorb nutrients better when the soil pH is between 5.5 and 7. That’s when microbial activities are at their highest levels. [[1]]
5. Test for Natural Organisms
Natural organisms thrive in healthy soil. They’re useful for providing aeration and fertilization, while earthworm castings deliver nutrients, organic matter, enzymes, and bacteria.
A simple visual check at random times can let you know if any natural organisms are thriving in your soil. If you see fungi, earthworms, or other invertebrates coming out when it rains, you’re in good shape. Find out more about fungi in your garden in our Why Are Mushrooms Growing in My Garden post.
When it hasn’t rained for a while, you can check your soil to see what natural organisms are present.
- Dig to a depth of at least eight inches before collecting a soil sample.
- Remove the soil, placing it on a tray for examination.
- Count the total number of organisms found on the tray, using a small stick to probe for different particles.
- If you see more than ten, your soil is likely healthy. If there is less than that, some compost can help you fortify its nutrient base.
You can dig about six inches deep to see how many earthworms are present in the soil. If you have at least three in that sample, things are likely healthy. [[1]]
The exception is when you live in a hot climate. Since earthworms prefer cool soil, you won’t find them near the surface.
6. Test for Water Infiltration
Good soil allows water to enter the surface and move through it easily. When that structure is present, the excess fluids can drain quickly to avoid root rot or oversaturation problems.
You can test for this quality by watering the ground at a specific place until a small pool form on the surface.
Set a timer. Healthy soils should only take a few minutes to absorb the surface moisture. If it takes more than 30 minutes for the pool to disappear, things could be more compacted than you want them to be for plants.
Another way to test this quality is to use an empty can. Remove the top and bottom lids, pushing the cylinder through the soil until only a few inches remain above the surface.
Fill the can with water so that you can check the absorption rate. If you see the levels drop by an inch or less per hour, it means you’ll need to amend the soil to support healthy plant growth.
7. Use a Soil Testing Kit
When you purchase a soil testing kit, you’ll get everything needed to determine how healthy things are.
Most home soil testing kits are made to test the pH levels. You’ll receive tablets and vials, along with a chart that helps to interpret your results.
If you purchase a testing meter, the only thing you need to do is insert the probe into the soil until you can read the results.
Before preparing a soil sample, you’ll need a clean bucket, trowel, and plastic container. Do not use anything metal because the materials could skew the results.
- Make sure to take the time to clean the tools being used for the soil sample collection to ensure an accurate result occurs.
- Dig five holes in the planting area approximately six to eight inches deep.
- Take a half-inch slide from along the side of one of the holes, placing it in the bucket. Repeat this step for the other four holes.
- Collect samples from areas where similar plants will be growing.
- Mix the soil in the bucket before spreading it out on newsprint to dry it out. Collect the amount the test kit requires.
Wet soils can give a false result, so you’ll want to ensure the material is adequately dry before testing. It often helps to check more than once to verify the information.
How to Submit Soil Samples for Professional Testing
Most DIY soil tests and retail kits provide an accurate estimate of what to expect. If you’re planting a small garden, those methods are usually good enough to find the right way to amend things for a healthy growing season.
Large-scale growers often need different tests that DIY kits don’t currently provide. Here are some examples of information that a professional testing result can offer.
- Boron Test. This option determines how much of this water-extractable element is in the soil. It’s often used for areas where legumes, alfalfa, or clover are grown in sandy areas. [[1]]
- Micronutrient Test. Growers use this test to determine how much copper, iron, manganese, and zinc are in the soil. This information helps grow specialty monocrops like sorghum or corn. [[2]]
- Salinity Test. With this soil test, a saturate paste extra measures solubility levels, electrical conductivity, and pH in the soil. The Sodium Adsorption Ratio gets calculated from that information, letting you see how much salt remains after brine spills or rainfall evaporation occurs. [[3]]
Soil samples should not be stored for a long time before shipping them to a laboratory for examination. Extended storage can cause the nitrate-nitrogen ratio to change, providing something of minimal value in your current environmental situation.
How to Collect Soil Samples for a Laboratory
Your County Extension Office (or similar oversight agency) provides soil sample bags, information sheets, and sample collection instructions. [[1]]
You would fill the sample bag with approximately one pint of composite soil. If your County Extension doesn’t provide this option, collect a similar amount in a plastic container.
The field you’re working on should get split into multiple tracts when you collect samples.
If the land has seen several land-use activities over the years, ranging from cropping to pasture, it might be necessary to produce several samples in each area.
The tools used to collect the soil samples depend on the conditions found at the site. What you use must core or slice through the surface to reach the desired level for testing.
If you’re not using an auger or tube to collect a core sample, you’d want to take a slice from the middle of your trowel or shovel. Avoid taking dirt from the edges to ensure an accurate result occurs.
The number of samples you’ll need depends on how much space is under evaluation. If a quarter-acre lawn or garden is getting worked, the laboratory might require five to seven samples to have a representative composite.
When you’re in a field of up to 40 acres, getting 15 slices or cores per composite sample might be necessary to ensure the information is accurate
Although six inches is the average depth used to collect a soil sample, stratification concerns could come into play for some testing needs. Fields that receive limited rain, no irrigation, and minimal tillage might need to dig to 9 inches or more below the surface for a professional examination.
If the fertilizer was placed deeper in the soil, the sampling depth might need to be adjusted.
When you take the time to discover the information your soil offers, it’s much easier to know what to do to grow healthy plants. Whether you choose a professional examination or a DIY method, these testing methods can let you know if anything is needed for healthy plant growth.
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[[1]] https://bio.libretexts.org/Bookshelves/Microbiology/Book%3A_Microbiology_(Boundless)/16%3A_Microbial_Ecology/16.2%3A_Soil_and_Plant_Microbiology/16.2A%3A_Soil_Composition
[[2]] https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052208.pdf [[3]] https://www.canr.msu.edu/news/earthworms_can_be_an_indicator_of_soil_health
[[4]] https://ods.od.nih.gov/factsheets/Boron-HealthProfessional/
[[5]] https://www.greenmatters.com/p/what-is-monocropping
[[6]] https://www.ars.usda.gov/ARSUserFiles/20360510/pdf_files/p1058.pdf [[7]] https://www.domyown.com/what-is-an-extension-office-a-683.html
